The present invention relates to a seat-load measuring apparatus mounted under a seat rail for guiding a seat of a vehicle, such as a car, so as to measure the load imposed on the vehicle seat.
As this type of seat-load measuring apparatus, seat-load measuring apparatuses 104 have been proposed which are mounted under seat rails 103 for guiding a vehicle seat 102, on which a person 101 sits, in order to measure the load imposed on the vehicle seat 102, as shown in FIGS. 10(A) to 10(C) (for example, see Japanese Unexamined Patent Application Publication No. 2000-258234, hereinafter “Patent Document 1”).
In each seat-load measuring apparatus 104, a lower surface of a base 105 that has an upward-pointing angular-U shape in cross section is fixed to a seat mounting section 107 of a vehicle body with seat brackets 106 at the front and rear ends therebetween, and the seat rail 103 and the base 105 are connected by a pin bracket (hereinafter, also referred to as a rail bracket) 108 serving as a connecting bracket that has a downward-pointing angular-U shape in cross section. In this case, the seat rail 103 is firmly connected to the flat upper surface of the pin bracket 108, and a bracket pin (hereinafter, also referred to as a stopper bolt) 109 is passed through pin holes 108a and 108b provided in the left and right side plates of the pin bracket 108 and pin holes 105a and 105b provided in the left and right side plates of the base 105, thereby connecting the seat rail 103 to the base 105.
On the other hand, a seat-load measuring apparatus has been proposed which ensures measuring accuracy without any influence of manufacturing errors of a vehicle floor by placing a seat rail between the seat-load measuring apparatus and the vehicle floor and absorbing the manufacturing errors of the vehicle floor by a clearance formed by a sliding contact in the seat rail (for example, see Japanese Unexamined Patent Application Publication No. 2002-116081, hereinafter “Patent Document 2”).
The seat-load measuring apparatus 104 disclosed in Patent Document 1 described above is interposed between the seat bracket 106 fixed to the seat mounting section 107 of the vehicle body and the seat rail 103, assembly stress may be produced in the seat-load measuring apparatus 104 by the influence of the upper surface of the seat mounting section 107 of the vehicle body. When the assembly stress is produced in the seat-load measuring apparatus 104, the seat-load measuring apparatus 104 cannot ensure a sufficient measuring accuracy.
In a case in which a heavy load is imposed on the pin bracket 108 that connects the seat rail 103 and the base 105 of the seat-load measuring apparatus 104, for example, in a vehicle collision, the pin bracket 108 must have a sufficient strength to support the heavy load.
However, in the connecting structure for the seat rail 103 and the base 105 of the seat-load measuring apparatus 104 disclosed in Patent Document 1 described above, only the bracket pin 109 extends through the pin holes 105a and 105b simply provided in the left and right side plates of the base 105 having an upwardly-pointing angular-U shape in cross section and the pin holes 108a and 108b simply provided in the left and right side plates of the pin bracket 108 having a downwardly-pointing angular-U shape in cross section. Therefore, the pin bracket 108 has a limitation of having a sufficient strength. That is, the pin bracket 108 can be increased to some extent by increasing the dimensions of portions 108c and 108d of the pin bracket 108 where the pin holes 108a and 108b are formed (for example, the thicknesses, and the distances from the pin holes 108a and 108b to the outer peripheral edge of the pin bracket 108). However, in such a case in which the dimensions of the portions of the pin bracket 108 having the pin holes 108a and 108b are simply increased, layout restrictions are increased, and mounting flexibility is reduced.
Although a heavy load, for example, in a vehicle collision can be, of course, supported by the connecting structure using the pin bracket 108 disclosed in the above publication, it is desirable to more reliably support such a heavy load without increasing layout restrictions.
In the seat-load measuring apparatus disclosed in Patent Document 2 described above, the seat rail is interposed between the seat-load measuring apparatus and the vehicle floor, and manufacturing errors of the vehicle floor are absorbed by the clearance produced by the sliding contact in the seat rail. This overcomes the problem of an insufficient measuring accuracy in Patent Document 1 described above.
In the seat-load measuring apparatus disclosed in Patent Document 2, however, an operation hole or the like must be formed in the base member, in a manner similar to that in Patent Document 1 described above, and this decreases the strength of the base member.
Although the base member disclosed in Patent Document 2 described above can support a heavy load produced, for example, in a vehicle collision, it is desirable to more reliably support such a heavy load without increasing layout restrictions.
The present invention has been made in view of such circumstances.